Information storage devices using magnetic domain wall movement and methods of manufacturing the same

ABSTRACT

In an information storage device, a writing magnetic layer is formed on a substrate and has a magnetic domain wall. A connecting magnetic layer is formed on the writing magnetic layer, and an information storing magnetic layer is formed on an upper portion of side surfaces of the connecting magnetic layer. A reader reads information stored in the information storing magnetic layer.

PRIORITY STATEMENT

This non-provisional U.S. patent application claims priority under 35U.S.C. §119 to Korean Patent Application No. 10-2006-0138862, filed onDec. 29, 2006, Korean Patent Application No. 10-2006-0133095, filed onDec. 22, 2006, and Korean Patent Application No. 10-2006-0138866, filedon Dec. 29, 2006 in the Korean Intellectual Property Office, the entirecontents of all of which are incorporated herein by reference.

BACKGROUND Description of the Related Art

A conventional hard disk drive (HDD) is a device that reads and writesinformation by rotating a magnetic recording medium in a disk form andmoving a reading/writing head above the magnetic recording medium.Conventional HDDs are non-volatile data storage devices capable ofstoring relatively large amounts of data on the order of 100 gigabytes(GB) of data or more. Conventional HDDs may be used as a main storagedevice in computers.

A conventional HDD may include a relatively large amount of moving ormechanical parts. These moving parts may be susceptible to variousmechanic faults when the HDD is moved and/or subject to shock.Mechanical faults may decrease mobility and/or reliability conventionalHDDs. These moving parts may also increase manufacturing complexity,costs of conventional HDDs, increase power consumption, and/or generatenoise. For example, when size of conventional HDDs is reduced,manufacturing complexity and/or costs may increase.

An example of an alternative information storage device is a datastorage device in which magnetic domain walls of a magnetic material aremoved.

Magnetic fine regions constituting a magnetic body are referred to asmagnetic domains. In these magnetic domains, the direction of themagnetoelectricity or the direction of all magnetic moments isidentical. The size of the magnetic domains and the direction of themagnetization may be controlled by the property, shape, size of themagnetic material and/or external energy.

A magnetic domain wall is a boundary between magnetic domains havingdifferent magnetization directions, and may be moved by a current and/ora magnetic field applied to the magnetic material.

Magnetic domains may be passed through pinned reading/writing heads bymoving the magnetic domain wall to enable reading/writing withoutrotation of recording medium. Information storage devices using magneticdomain wall movement may store a relatively large amount of data and maynot include moving parts.

SUMMARY

Example embodiments relate to information storage devices, for example,an information storage device using magnetic domain wall movement andmethods of manufacturing an information storage device.

Example embodiments provide information storage devices using magneticdomain wall movement, which may store a relatively large amount ofinformation, provide improved mobility and/or reliability because movingparts are not required. Example embodiments also provide methods ofmanufacturing the data storage device.

At least one example embodiment provides an information storage deviceusing magnetic domain wall movement. According to at least this exampleembodiment, a writing magnetic layer may be formed on a substrate. Themagnetic wiring layer may include at least one magnetic domain wall. Atleast one connecting magnetic layer may be formed on the at least onewriting magnetic layer. At least one information storing magnetic layermay be formed on an upper portion of a side surface of the at least oneconnecting magnetic layer. A reader may be configured to readinformation stored in the at least one information storing magneticlayer.

According to at least some example embodiments, the information storingmagnetic layer may be formed on an upper portion of a first side surfaceof the connecting magnetic layer and an upper portion of a second sidesurface. The second side surface may be opposite to the first sidesurface. The information storing magnetic layer may include a firstregion and a second region. The first region may cover an upper portionof the side surface of the connecting magnetic layer. The second regionmay be formed on either end of the first region. The second region maybe perpendicular to the first region. The second region of theinformation storing magnetic layer may be inclined relative to thesubstrate. Alternatively, the second region of the information storingmagnetic layer may be perpendicular to the substrate. The height of theinformation storing magnetic layer may be greater than the thickness ofthe information storing magnetic layer.

According to at least some example embodiments, a plurality ofconnecting magnetic layers may be formed in a direction perpendicular tothe substrate, and a plurality of information storing magnetic layersmay be formed on at least two side surfaces of each of the plurality ofconnecting magnetic layers. A plurality of writing magnetic layers maybe spaced apart on the substrate, and a plurality of connecting magneticlayers may be formed along each of the writing magnetic layers.

According to at least some example embodiments, the writing magneticlayer and the information storing magnetic layer may be perpendicular orparallel to each other. A magnetic anisotropic energy of the writingmagnetic layer may be in the range of about 2×10³ to about 10⁷ J/m³,inclusive. The connecting magnetic layer may have a stack structureincluding a first connecting magnetic layer and a second connectingmagnetic layer. A magnetic anisotropic energy of the first connectingmagnetic layer may be in the range of about 10 to about 10³ J/m³,inclusive. A magnetic anisotropic energy of the second connectingmagnetic layer may be in the range of about 10 to about 10⁷ J/m³,inclusive. A magnetic anisotropic energy of the information storingmagnetic layer may be in the range of about 2×10³ to about 10⁷ J/m³,inclusive.

At least one other example embodiment provides a method of manufacturingan information storage device. According to at least this exampleembodiment, a writing magnetic layer and a first insulating layer may beformed on the substrate. The first insulating layer may cover thewriting magnetic layer. An opening may be formed by patterning the firstinsulating layer. The opening may include a first groove and a secondgroove. The first and the second grooves may expose the writing magneticlayer. The first grove may be formed in the second groove and may have awidth less than the second groove. A first connecting magnetic layer maybe formed in the first groove, and a second connecting magnetic layermay be formed on the first connecting magnetic layer. A ring-typemagnetic layer may be formed. The ring-type magnetic layer may cover aside surface of the second connecting magnetic layer and a sidewall ofthe second groove. An end portion of the ring-type magnetic layer may beremoved.

According to at least some example embodiments, the opening may beformed using a nano-imprint process with a master stamp having amulti-step structure. The sidewall of the second groove may be inclinedor perpendicular relative to the substrate.

According to at least some example embodiments, in forming the ring-typemagnetic layer, a first magnetic layer may be formed on an upper surfaceof the first insulating layer, an upper surface and a side surface ofthe second connecting magnetic layer, and a bottom surface and asidewall of the second groove. A protective layer may be formed to covera portion of the first magnetic layer which is on the side surface ofthe second connecting magnetic layer and the sidewall of the secondgroove. Portions of the first magnetic layer formed on the bottomsurface of the second groove, the upper surface of the second connectingmagnetic layer and the upper surface of the first insulating layer maybe removed by etching the first magnetic layer using the protectivelayer as an etching mask.

According to at least some example embodiments, in forming theprotective layer, a second insulating layer may be formed on the firstmagnetic layer. Portions of the second insulating layer formed on abottom surface of the second groove, an upper surface of the secondconnecting magnetic layer and an upper surface of the first insulatinglayer may be removed by patterning the second insulating layer. Thesecond insulating layer may be patterned using a nano-imprint process.

According to at least some example embodiments, in forming the ring-typemagnetic layer, a first magnetic layer may be formed on an upper surfaceof the first insulating layer, an upper surface and a side surface ofthe second connecting magnetic layer and a bottom surface and a sidewallof the second groove. Portions of the first magnetic layer formed on abottom surface of the second groove, an upper surface of the secondconnecting magnetic layer and an upper surface of the first insultinglayer may be removed using anisotropic-etching on the first magneticlayer.

According to at least some example embodiments, the first and secondconnecting magnetic layers may be formed using electro plating. Thefirst and second connecting magnetic layers may be formed of the same,substantially the same or different materials.

At least one other example embodiment provides a method of manufacturingan information storage device. According to at least this exampleembodiment, a writing magnetic layer and a first insulating layer may beformed on the substrate. The first insulating layer may cover thewriting magnetic layer. A first groove may be formed to expose thewriting magnetic layer by patterning the first insulating layer. A firstconnecting magnetic layer may be formed in the first groove. A secondinsulating layer may be formed on the first connecting magnetic layerand the first insulating layer. A second groove may be formed bypatterning the second insulating layer to expose both of the firstconnecting magnetic layer and at least a portion of the first insulatinglayer. A second connecting magnetic layer may be formed on the firstconnecting magnetic layer in the second groove. A ring-type magneticlayer may be formed to cover a side surface of the second connectingmagnetic layer and a sidewall of the second groove. An end portion ofthe ring-type magnetic layer may be removed.

At least one other example embodiment provides a method of manufacturingan information storage device. According to at least this method, awriting magnetic layer and a first insulating layer may be formed on asubstrate. The first insulating layer may cover the writing magneticlayer. An opening may be formed in the first insulating layer. Theopening may expose the writing magnetic layer and include at least afirst groove. The first grove may be formed in a second groove, and thefirst groove may have a width less than a width of the second groove. Afirst connecting magnetic layer may be formed in the first groove, and asecond connecting magnetic layer may be formed on the first connectingmagnetic layer. A ring-type magnetic layer covering a side surface ofthe second connecting magnetic layer and a sidewall of the second groovemay be formed, and an end portion of the ring-type magnetic layer may beremoved.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will become more apparent by describing in detailthe example embodiments shown in the attached drawings in which:

FIG. 1 is a perspective view illustrating an information storage deviceaccording to an example embodiment;

FIG. 2A through 2E are perspective views illustrating an example writingoperation according to an example embodiment;

FIG. 3 is a perspective view illustrating an information storage deviceaccording to another example embodiment;

FIGS. 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A and 12A are cross-sectional viewsfor illustrating a method of manufacturing an information storage deviceaccording to an example embodiment; and

FIGS. 4B, 5B, 6B, 7B, 8B, 9B, 10B, 11B and 12B are cross-sectional viewsof FIGS. 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A and 12A, respectively, whichare taken along a line b-b′.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Various example embodiments of the present invention will now bedescribed more fully with reference to the accompanying drawings inwhich some example embodiments of the invention are shown. In thedrawings, the thicknesses of layers and regions are exaggerated forclarity.

Detailed illustrative embodiments of the present invention are disclosedherein. However, specific structural and functional details disclosedherein are merely representative for purposes of describing exampleembodiments of the present invention. This invention may, however, maybe embodied in many alternate forms and should not be construed aslimited to only the embodiments set forth herein.

Accordingly, while example embodiments of the invention are capable ofvarious modifications and alternative forms, embodiments thereof areshown by way of example in the drawings and will herein be described indetail. It should be understood, however, that there is no intent tolimit example embodiments of the invention to the particular formsdisclosed, but on the contrary, example embodiments of the invention areto cover all modifications, equivalents, and alternatives falling withinthe scope of the invention. Like numbers refer to like elementsthroughout the description of the figures.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of example embodiments of thepresent invention. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between”, “adjacent” versus “directlyadjacent”, etc.).

It will be understood that when an element or layer is referred to asbeing “formed on” another element or layer, it can be directly orindirectly formed on the other element or layer. That is, for example,intervening elements or layers may be present. In contrast, when anelement or layer is referred to as being “directly formed on” to anotherelement, there are no intervening elements or layers present. Otherwords used to describe the relationship between elements or layersshould be interpreted in a like fashion (e.g., “between” versus“directly between”, “adjacent” versus “directly adjacent”, etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments of the invention. As used herein, the singular forms “a”,“an” and “the” are intended to include the plural forms as well, unlessthe context clearly indicates otherwise. It will be further understoodthat the terms “comprises”, “comprising,”, “includes” and/or“including”, when used herein, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

FIG. 1 is a perspective view illustrating an information storage device(hereinafter, referred to as “information storage device”) according toan example embodiment.

Referring to FIG. 1, a writing magnetic layer 100 having magnetic domainwall movement properties may be formed on a substrate (not shown). Aconnecting magnetic layer 200 may be formed on a first (e.g., given ordesired) region of the writing magnetic layer 100. The connectingmagnetic layer 200 may have a stack structure in which first and secondconnecting magnetic layers 200 a and 200 b are stacked (e.g.,sequentially). Side surfaces of the first and second connecting magneticlayers 200 a and 200 b may be inclined or perpendicular relative to thesubstrate. An information storing magnetic layer 300 may be formed on anupper portion of the side surfaces of the connecting magnetic layer 200.

For example, information storing magnetic layer 300 may be formed on twoopposite side surfaces of the second connecting magnetic layer 200 b.Alternatively, the information storing magnetic layer 300 may be formedon different surfaces of the second connecting magnetic layer 200 b.According to the surfaces on which the information storing magneticlayer 300 is formed, the writing magnetic layer 100 and the informationstoring magnetic layer 300 may be perpendicular or parallel to eachother. The information storing magnetic layer 300 may include a firstregion 230 covering the side surface of the second connecting magneticlayer 200 b and a second region 260 formed on both edges of the firstregion 230. The second region 260 may be formed perpendicular to thefirst region 230. According to at least some example embodiments, asingle second connecting magnetic layer 200 b may connect four secondregions 260.

The height “H” and thickness “T” of the information storing magneticlayer 300 may be in the range of about 1 to about 100 nm, inclusive. Theheight “H” may be greater than the thickness “T”. For example, theheight “H” may be about 50 nm and the thickness “T” may be about 10 nm.An interval between the second regions 260, which are on differentplanes, may be more than about 10 nm, for example, in the range of about10 to about 100 nm, inclusive. The second region 260 may be inclinedwith respect to the substrate by a given angle. According to at leastone example embodiment, the second regions 260 may be perpendicular tothe substrate.

The magnetic anisotropic energy of the writing magnetic layer 100 andthe information storing magnetic layer 300 may be in the range of about2×10³ to about 10⁷ J/m³, inclusive. The magnetic anisotropic energy ofthe first connecting magnetic layer 200 a may be in the range of about10 to about 10³ J/m³, inclusive. The magnetic anisotropic energy of thesecond connecting magnetic layer 200 b may be in the range of about 10to about 10⁷ J/m³, inclusive. For example, the writing magnetic layer100 and the information storing magnetic layer 300 may be aferromagnetic layer, and the first connecting magnetic layer 200 a maybe a soft magnetic layer. The second connecting magnetic layer 200 b maybe a ferromagnetic layer or a soft magnetic layer.

The writing magnetic layer 100 and the information storing magneticlayer 300 may be formed of a material selected from the group includingor consisting of CoPt, FePt, an alloy thereof or the like, and the firstconnecting magnetic layer 200 a may be formed of a material selectedfrom the group including or consisting of Ni, Co, NiCo, NiFe, CoFe,CoZrNb, CoZrCr an alloy thereof or the like. The second connectingmagnetic layer 200 b may be formed of a material selected from the groupincluding or consisting of Ni, Co, NiCo, NiFe, CoFe, CoZrNb, CoZrCr analloy thereof or the like, or alternatively, a material selected fromthe group including or consisting of CoPt, FePt, an alloy thereof or thelike.

A reader 400 for reading information stored in the information storingmagnetic layer 300 may be formed on a given or desired region of theinformation storing magnetic layer 300. The reader 400 may be a magneticresistance sensor such as a tunnel magneto resistance (TMR) sensor, agiant magneto resistance (GMR) sensor or the like, which are well-known.The reader 400 may be formed on a bottom surface, an upper surface or aside surface of the information storing magnetic layer 300.Alternatively, the magnetic resistance sensor 400 may be formed on anupper surface or a bottom surface of the writing magnetic layer 100.

First and second wires C1 and C2 may be formed on either of ends E1 andE2 of the writing magnetic layer 100. The first and second wires C1 andC2 may be used to supply a current. Third through sixth wires C3 to C6may be formed on ends of the second regions 260. Third through sixthwires C3 to C6 may also be used to supply a current. Each of the firstthrough sixth wires C1 to C6 may be connected to a driving device (notshown) such as a transistor. When a current having a given direction issupplied to the writing magnetic layer 100 through the first and secondwires C1 and C2, magnetic domain walls in the writing magnetic layer 100may be moved in a given direction. Because magnetic domain walls aremoved in a direction of electrons, the direction of magnetic domain wallmovement may be opposite to that of the current. A current for movingmagnetic domain walls may be supplied between one of the first andsecond wires C1 and C2 and one of the third through sixth wires C3 toC6, or a current for moving magnetic domain walls may be supplied to aplurality (e.g., any two) of the third through sixth wires C3 to C6.

By appropriately moving magnetic domain walls in the writing magneticlayer 100, the connecting magnetic layer 200 and the information storingmagnetic layer 300, data may be recorded in the information storingmagnetic layer 300. Hereinafter, an example writing operation of theinformation storage device according to an example embodiment will bedescribed in detail referring to FIGS. 2A through 2E. Like referencenumerals in FIGS. 2A through 2E and FIG. 1 denote like elements.

Referring to FIG. 2A, the writing magnetic layer 100 may include aplurality of (e.g., two) magnetic domains D1 and D2 and one magneticdomain wall (hereinafter, referred to as “first magnetic domain wallDW1”) positioned there between. The first and second magnetic domains D1and D2 may be formed in the writing magnetic layer 100 in various ways.For example, a soft magnetic layer may be formed on one end of aferromagnetic layer, which is to be used as the writing magnetic layer100, and an external magnetic field may be supplied to the ferromagneticlayer and the soft magnetic layer. Accordingly, the ferromagnetic layercontacting the soft magnetic layer may have a magnetization directiondifferent from that of other parts of the writing magnetic layer 100.According to the number and the location of the soft magnetic layer, thenumber of magnetic domains formed in the writing magnetic layer 100 maybe different.

In FIG. 2A, the first magnetic domain wall DW1 may be positioned closerto the end E2 of the writing magnetic layer 100. The first magneticdomain D1, the connecting magnetic layer 200 and the information storingmagnetic layer 300 may be magnetized in a first direction M1. The secondmagnetic domain D2 may be magnetized in a second direction M2.

FIG. 2B is a perspective view illustrating a case in which the firstmagnetic domain wall DW1 of the information storage device of FIG. 2A ismoved. The first magnetic domain wall DW1 may be moved by supplying acurrent from the first wire C1 to the second wire C2.

Referring to FIG. 2B, by moving the first magnetic domain wall DW1, thesecond magnetic domain D2 may extend to be below the first connectingmagnetic layer 200 a. As a result, a magnetization direction of thefirst connecting magnetic layer 200 a may change (e.g., be reversed) toa second direction M2. This is because the first connecting magneticlayer 200 a is a soft magnetic layer in which magnetization reversal maybe performed more easily. When the magnetization direction of the firstconnecting magnetic layer 200 a is reversed, the magnetization directionof the second connecting magnetic layer 200 b may be reversed. This isbecause if the second connecting magnetic layer 200 b and the firstconnecting magnetic layer 200 a have the same or substantially the samemagnetization direction, energy may be more stable than when thedirections are opposite.

When the magnetic anisotropic energy of the second connecting magneticlayer 200 b is less than that of the writing magnetic layer 100,magnetization reversal on the second connecting magnetic layer 200 b maybe more easily performed. Such magnetization reversal may occurserially. If a plurality of connecting magnetic layers are stackedperpendicularly, magnetization reversal may occur serially from a bottomlayer of the connecting magnetic layer 200 to a top layer of theconnecting magnetic layer 200.

According to such magnetization reversal, second and third magneticdomain walls DW2 and DW3 may be formed between the information storingmagnetic layer 300 and the second connecting magnetic layer 200 b.

Referring to FIG. 2C, a current may be supplied from a fifth wire C5 toa second wire C2 to move the second magnetic domain wall DW2 in thesecond region 260 connected to the fifth wire C5 by one magnetic domainunit. Thus, a third magnetic domain D3 may be formed in the secondregion 260 connected to the fifth wire C5. Data corresponding to thethird magnetic domain D3 may be ‘0’.

Referring to FIG. 2D, a current may be supplied from the second wire C2to the first wire C1, and as such the first magnetic domain wall DW1 maymove from the end E1 towards the end E2. Thus, the first magnetic domainD1 may extend to be below the first connecting magnetic layer 200 a. Asa result, the magnetization directions of the first and secondconnecting magnetic layers 200 a and 200 b may be reversed to the firstdirection M1. Accordingly, a fourth magnetic domain wall DW4 may beformed on a boundary between the second region 260 connected to thefifth wire C5 and the second connecting magnetic layer 200 b.

Referring to FIG. 2E, a current may be supplied from the fifth wire C5to the first wire C1, to move a fourth magnetic domain wall DW4 in thesecond region 260 connected to the fifth wire C5 by one magnetic domainunit. Thus, a fourth magnetic domain D4 may be formed in the secondregion 260 connected to the fifth wire C5. Data corresponding to thefourth magnetic domain D4 may be ‘1’. The third magnetic domain D3 mayalso move by one magnetic domain unit. Accordingly, data correspondingto ‘0’ and ‘1’ may be stored in the second region 260. Using exampleembodiments, binary data may be stored in a given region of theinformation storing magnetic layer 300.

Although the writing magnetic layer 100, the connecting magnetic layer200 and the information storing magnetic layer 300 are shown as having aperpendicular magnetic anisotropy in FIGS. 2A through 2E, the writingmagnetic layer 100, the connecting magnetic layer 200 and theinformation storing magnetic layer 300 may have a horizontal orsubstantially horizontal magnetic anisotropy.

In information storage devices according to at least some exampleembodiments, data may be recorded by moving magnetic domain walls in thewriting magnetic layer 100, the connecting magnetic layer 200 and theinformation storing magnetic layer 300. Accordingly, moving mechanicalparts, such as those used in conventional HDDs, may not be required.

Although not illustrated, a magnetic domain may be moved to a lowerportion of the reader 400 and a given read current may be supplied tothe reader 400 to read the data stored in the magnetic domain. Duringreading and/or writing operations according to at least some exampleembodiments, a portion of the information storing magnetic layer 300and/or the writing magnetic layer 100 may be used as a buffer area fortemporally storing data.

Referring back to FIG. 1, an information storage device may include aplurality of writing magnetic layers 100, a plurality of connectingmagnetic layers 200 and a plurality of information storing magneticlayers 300. For example, the connecting magnetic layers 200 may bestacked in a direction perpendicular to the substrate, and theinformation storing magnetic layers 300 may be formed on at least twoside surfaces of each of the connecting magnetic layers 200. The writingmagnetic layers 100 may be spaced apart on the substrate, and theconnecting magnetic layers 200 may be formed along a length direction ofeach of the writing magnetic layers 100. The information storingmagnetic layers 300 may be formed on at least two side surfaces of eachof the connecting magnetic layers 200. For example, if one connectingmagnetic layer 200 and two information storing magnetic layers 300connected to the connecting magnetic layers 200 is regarded as onecolumn structure, a plurality of the column structures may be stacked ontop of each other.

FIG. 3 is a perspective view illustrating an information storage devicehaving a multi-stack structure according to an example embodiment.

Referring to FIG. 3, when information storing magnetic layers 300 havethe multi-stack structure, a second region 260 of each of theinformation storing magnetic layer 300 may be longer for columnstructures formed higher up in the multi-stack structure so that wires(now shown) may be more easily fabricated for connecting the secondregion 260 and driving devices (not shown). For example, second regions260 of each of the information storing magnetic layers 300 in each ofthe plurality of stack structures may have a different length. Thestructures illustrated in FIG. 3 may be repeatedly formed to be parallelor substantially parallel to X and/or Y axes. The directions of X and Yaxes are the same as those of FIG. 1.

Example embodiments of information storage devices having themulti-stack structure may store a relatively large amount ofinformation. For example, because one of the connecting magnetic layers200 is connected to a plurality of (e.g., four) second regions 260 inthe information storage device, the information storage device may storemore information than an information storage device in which the ratioof connecting magnetic layer 200 to information storage track is 1:1 or1:2.

A method of manufacturing of an information storage device usingmagnetic domain wall movement according to an example embodiment(hereinafter, referred to as “manufacturing method”) will be described.

FIGS. 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A and 12A are cross-sectional viewstaken along a first line and illustrate a manufacturing method accordingto an example embodiment. FIGS. 4B, 5B, 6B, 7B, 8B, 9B, 10B, 11B and 12Bare views corresponding to FIGS. 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A and12A, respectively, which are taken along a second line and illustrate amanufacturing method according to an example embodiment. The first linecorresponds to a line a-a′ of FIG. 1, and the second line corresponds tolines b-b′ of FIGS. 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A and 12A.

Referring to FIGS. 4A and 4B, a writing magnetic layer 100 may be formedon a substrate 10. The writing magnetic layer 100 may be the same orsubstantially the same as a writing magnetic layer 100 of FIG. 1. Afirst insulating layer 20 may be formed on the substrate 10 to cover thewriting magnetic layer 100. The first insulating layer 20 may be a resinlayer or the like.

A first master stamp 50 may have a multi-step structure and may bepositioned above the first insulating layer 20. The first master stamp50 may be fabricated using a nano-patterning method such as E-beamlithography or the like. The first master stamp 50 may include a firstprotrusion P1 and a second protrusion P2 formed on central or centerportion of the first protrusion P1. Sidewalls of the first and secondprotrusions P1 and P2 may be inclined due to slope etching. An angle(e.g., acute angle) between each of the sidewalls of the first andsecond protrusions P1 and P2 and the substrate 10 is referred to hereinas the first angle. The first angle may depend on etching conditionsduring manufacturing of the first master stamp 50.

Referring to FIGS. 5A and 5B, a first insulating layer 20 may bepatterned by imprinting the first insulating layer 20 using the firstmaster stamp 50. The first master stamp 50 may be removed from the firstinsulating layer 20. The first master stamp 50 may be used repeatedly.

FIGS. 6A and 6B are cross-sectional views illustrating the firstinsulating layer 20 after the first master stamp 50 is removed.Referring to FIGS. 6A and 6B, an opening 1 may be formed using animprint process with the first master stamp 50. The opening 1 may exposea portion of the writing magnetic layer 100. The opening 1 may include afirst groove H1 and a second groove H2 formed above the first groove H1and having a width greater than the first groove H1. Sidewalls of thefirst and second grooves H1 and H2 may be inclined. A part of the firstinsulating layer 20 may remain on a bottom of the first groove H1. Sucha remaining portion of the first insulating layer 20 may be removedusing reactive ion etching (RIE), plasma ashing or the like.

Referring to FIGS. 7A and 7B, a first connecting magnetic layer 200 amay be formed in the first groove H1 using, for example, electroplating. The first connecting magnetic layer 200 a may be the same orsubstantially the same as the first connecting magnetic layer 200 a ofFIG. 1. The thickness of the first connecting magnetic layer 200 a maybe controlled by adjusting reaction conditions and/or reaction timesduring the electro plating such that the height of the first connectingmagnetic layer 200 a and the height of the first groove H1 correspond toone another.

A second connecting magnetic layer 200 b may be formed on the firstconnecting magnetic layer 200 a using electro plating. The secondconnecting magnetic layer 200 a may be the same or substantially thesame as the second connecting magnetic layer 200 b of FIG. 1, and mayhave a height similar or substantially similar to that of the secondgroove H2. The width of the second connecting magnetic layer 200 bmeasured along the x-axis may be greater than the width of the firstconnecting magnetic layer 200 a measured along the x-axis. The x-axismay be the same as that of FIG. 1.

Referring to FIGS. 8A and 8B, a magnetic layer 290 may be formed on anexposed surface of the second groove H2, an upper surface of the firstinsulating layer 20 and an exposed surface of the second connectingmagnetic layer 200 b. A second insulating layer 30 may be formed on themagnetic layer 290. The second insulating layer 30 may be a resin layeror the like.

A second master stamp 60 may be positioned on the second insulatinglayer 30. The second master stamp 60 may be fabricated using anano-patterning method such as E-beam lithography or the like. Accordingto at least one example embodiment, the second master stamp 60 may befabricated in a manner similar or substantially similar to the method ofmanufacturing the first master stamp 50. The second master stamp 60 mayinclude third and fourth protrusions P3 and P4, which may be spacedapart from each other. The third and fourth protrusions P3 and P4 eachmay have a shape and a size appropriate to be inserted into the secondgroove H2 on either side of the second connecting magnetic layer 200 b.The third and fourth protrusions P3 and P4 may be narrower than thesecond groove H2 in accordance with a process margin. Sidewalls of thethird and fourth protrusions P3 and P4 may be inclined. An angle (e.g.,acute angle) between each of sidewalls of the third and fourthprotrusions P3 and P4 and the substrate 10 may be referred to as asecond angle. The second angle may be greater than the first angle.

Referring to FIGS. 9A and 9B, a second insulating layer 30 may bepatterned by imprinting the second insulating layer 30 using the secondmaster stamp 60. After patterning, a portion of the second insulatinglayer 30 may remain to cover portions of the magnetic layer 290 formedon side surfaces of the second connecting magnetic layer 200 b andsidewalls of the second groove H2. Hereinafter, such remaining parts ofthe second magnetic layer 30 will be referred to as a sidewallprotective layer 30′.

The second master stamp 60 may be removed from the sidewall protectivelayer 30′ and the magnetic layer 290. The second master stamp 60 may beused repeatedly.

FIGS. 10A and 10B are cross-sectional views illustrating the state afterthe second master stamp 60 is removed. Referring to FIGS. 10A and 10B,portions of the magnetic layer 290 formed on a bottom surface of thesecond groove H2, an upper surface of the second connecting magneticlayer 200 b and an upper surface of the first insulating layer 20 may beexposed using an imprinting process with the second master stamp 60.

Referring to FIGS. 11A and 11B, the magnetic layer 290 may be etchedusing the sidewall protective layer 30′ as an etching mask, and portionsof the magnetic layer 290 formed on a bottom surface of the secondgroove H2, an upper surface of the second connecting magnetic layer 200b and an upper surface of the first insulating layer 20 may be removed.Accordingly, portions of the magnetic layer 290 corresponding to thesidewall protective layer 30′ may remain to cover side surfaces of thesecond connecting magnetic layer 200 b and side surfaces of the secondgroove H2. Hereinafter, such remaining portions of the magnetic layer290 may be referred to as a ring-type magnetic layer 290′. After formingthe ring-type magnetic layer 290′, the sidewall protective layer 30′ maybe removed.

An end portion E of the ring-type magnetic layer 290′ not contacting thesecond connecting magnetic layer 200 b may be removed. The end portion Eof the ring-type magnetic layer 290′ may be removed usingphotolithography methods or the like. For example, a photosensitivelayer having an opening exposing the end portion E of the ring-typemagnetic layer 290′ may be formed, and the end portion E of thering-type magnetic layer 290′ may be selectively removed using thephotosensitive layer as an etching mask.

As shown in FIGS. 12A and 12B, illustrates a state after the end portionE is removed. The ring-type magnetic layer 290′, of which the endportion E is cut, is referred to as an information storing magneticlayer 300. A reader (not shown) may be formed on a given region of theinformation storing magnetic layer 300.

Although an example embodiment of a method of manufacturing a structureof FIG. 1 has been described with regard to FIGS. 4A through 12B, suchmethod may be used in a method of manufacturing an information storagedevice having a multi-stack structure as shown in FIG. 3.

According to example embodiments of manufacturing methods, a pluralityof (e.g., two) grooves may be formed using one imprint process with amulti-step master stamp. Four second regions 260 connected to the oneconnecting magnetic layer 200 may be formed (e.g., simultaneously).According to example embodiments, information storage devices storing arelatively large amount of information may be produced by a relativelysmall number of processes.

Various changes to example embodiments may be made. For example, ifsidewalls of the first and second protrusions P1 and P2 of the firstmaster stamp 50 are perpendicular to the substrate 10, the ring-typemagnetic layer 290′ may be formed by anisotropic-etching the magneticlayer 290 rather than forming the second insulating layer 30. Becausethe second master stamp 60 is not used, the process may be simplified.If two master stamps having a single-step structure are used instead ofthe first master stamp 50 having a multi-step structure, the firstinsulating layer 50 may be formed using two operations, and the firstgroove H1 and the second groove H2 may be formed separately.

According to example embodiments, information storage devices may storerelatively large amounts of information, provide improved mobility,reliability and/or may be more easily produced using a relatively smallnumber of processes.

While example embodiments have been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in positionrelations of the writing magnetic layer, the connecting magnetic layerand the information storing magnetic layer may be made therein withoutdeparting from the spirit and scope of the present invention as definedby the following claims.

1. An information storage device comprising: at least one writingmagnetic layer formed on a substrate, the at least one writing magneticlayer having at least one magnetic domain wall; at least one connectingmagnetic layer formed on the at least one writing magnetic layer, atleast a portion of the at least one connecting magnetic layer directlycontacting the at least one writing magnetic layer; at least oneinformation storing magnetic layer formed on a portion of a side surfaceof the at least one connecting magnetic layer; and a reader for readinginformation stored in the at least one information storing magneticlayer.
 2. The information storage device of claim 1, wherein a first ofthe at least one information storing magnetic layers is formed on anupper portion of a first side surface of the connecting magnetic layerand a second of the at least one information storing magnetic layers isformed on an upper portion of a second side surface of the connectingmagnetic layer, the second side surface being opposite to the first sidesurface.
 3. The information storage device of claim 1, wherein the atleast one information storing magnetic layer includes, a first regioncovering the portion of the side surface of the connecting magneticlayer, and a second region formed on at least one end of the firstregion, the second region being formed perpendicular to the firstregion.
 4. The information storage device of claim 3, wherein the secondregion is inclined relative to the substrate.
 5. The information storagedevice of claim 3, wherein the second region is perpendicular to thesubstrate.
 6. The information storage device of claim 1, wherein theheight of the at least one information storing magnetic layer is greaterthan the thickness of the at least one information storing magneticlayer.
 7. The information storage device of claim 1, wherein the atleast one connecting magnetic layer includes a plurality of connectingmagnetic layers, each of the plurality of connecting magnetic layersbeing arranged perpendicular to the substrate and the at least oneinformation storing magnetic layers includes a plurality of informationstoring magnetic layers, at least two side surfaces of each of theplurality of connecting magnetic layers having one of the plurality ofinformation storing magnetic layers formed thereon.
 8. The informationstorage device of claim 1, wherein the at least one writing magneticlayers includes a plurality of writing magnetic layers, the plurality ofwriting magnetic layers being spaced apart from one another on thesubstrate, and the at least one connecting magnetic layer including aplurality of connecting magnetic layers, each of the plurality ofconnecting magnetic layers corresponding to one of the plurality ofwriting magnetic layers.
 9. The information storage device of claim 1,wherein the at least one writing magnetic layer and the at least oneinformation storing magnetic layer are formed perpendicular to oneanother.
 10. The information storage device of claim 1, wherein the atleast one writing magnetic layer and the at least one informationstoring magnetic layer are formed parallel to one another.
 11. Theinformation storage device of claim 1, wherein a magnetic anisotropicenergy of the at least one writing magnetic layer is in the range ofabout 2×10³ to about 10⁷ J/m³, inclusive.
 12. The information storagedevice of claim 1, wherein the at least one connecting magnetic layerhas a stack structure including a first connecting magnetic layer and asecond connecting magnetic layer.
 13. The information storage device ofclaim 12, wherein a magnetic anisotropic energy of the first connectingmagnetic layer is in the range of about 10 to about 10³ J/m³, inclusive.14. The information storage device of claim 12, wherein a magneticanisotropic energy of the second connecting magnetic layer is in therange of about 10 to about 10⁷ J/m³, inclusive.
 15. The informationstorage device of claim 1, wherein a magnetic anisotropic energy of theat least one information storing magnetic layer is in the range of about2×10³ to about 10⁷ J/m³, inclusive.
 16. An information storage devicecomprising: at least one writing magnetic layer formed on a substrate,the at least one writing magnetic layer having at least one magneticdomain wall; at least one connecting magnetic layer formed on the atleast one writing magnetic layer; at least one information storingmagnetic layer formed on a portion of a side surface of the at least oneconnecting magnetic layer; and a reader for reading information storedin the at least one information storing magnetic layer; wherein theinformation storage device is configured to write data in theinformation storage magnetic layer by applying a current passing throughthe information storage magnetic layer, the connecting magnetic layer,and the writing magnetic layer.